Current methods for manufacturing diamond films by microwave-plasma-assisted chemical vapor deposition (MP-CVD) are of limited effectiveness. The large amounts of energy, which are needed to obtain diamond of electronic quality at reasonable growth rates (about 2 μm/h), lead to heating of the walls. This process causes hydrogen atoms in the plasma, which activate the reaction, to recombine and not participate in the reaction. It is therefore necessary to install a constricting device for cooling the walls. In the proceedings of the Electrical Chemical Society (ECS) meeting held in San Francisco in 2001, it was proposed in “Diagnostics and modelling of moderate pressure microwave H2/CH4 plasmas obtained under pulsed mode” by a number of co-inventors to use a periodic pulsed discharge with a low duty cycle (the ratio of the time during which energy is emitted to the period of the discharge), in order to reduce the wall temperature, which is related to the average injected power, and therefore the recombination of hydrogen taking place thereon. Using such a pulsed discharge makes it possible to maintain a high temperature of the plasma, which is related to the power injected during the pulse, and therefore to obtain a higher concentration of hydrogen atoms in the plasma. Thus, a diamond film may be deposited at a higher rate for constant consumed power.